Portable devices, such as mobile phones, tablet devices, digital cameras, and other types of computing and electronic devices may be designed with a touchscreen for user input with a stylus or touch contact. Typically, a user can contact the touchscreen of a device to access the functionality of the device. For example, touchscreen contact may be used to open, close, and use applications, or to modify device settings. However, the data captured by a conventional touchscreen that is used with a passive stylus generally only indicates whether the stylus is contacting the touchscreen and, if so, the x-y position of the stylus on the touchscreen. Further, most capacitive or resistive touchscreens used with a passive stylus have difficulty determining whether the stylus is actually touching the touchscreen, or merely hovering close to it. This can limit the functionality of the touchscreen and/or cause the touchscreen to misinterpret user input.
In contrast, an active stylus is a powered input device that can measure contact pressure between the stylus and the touchscreen, and provide that information to the device to help distinguish between contact and hovering. However, to measure and transmit this data, an active stylus requires a battery or other power source inside the stylus. Further, the device receiving and processing the input information from an active stylus also uses additional device power.